A porous ionic polymer bionic carrier in a mixed matrix membrane for facilitating selective CO2 permeability

Inspired by the most efficient CO2 transport across natural biological membranes, a novel bionic channel facilitating CO2 permeation was realized via adding a filtering porous ionic polymer (PIP) in a mixed matrix membrane (MMM). A series of polymer of intrinsic microporosity (PIM-1) based MMMs were fabricated by three pyridine-based PIPs (PIP-Py-X) with different Cl−, Ac−, and BF4− anions as fillers. PIP-Py-X PIPs show highly selective CO2 adsorption capacity and perfect interfacial compatibility with the PIM-1 matrix. More significantly, acting as carriers, the movable anions in the MMMs efficiently facilitated the transport of adsorbed CO2 across the membranes. As a result, the obtained PIM-Py-Ac-15 MMM exhibited an excellent permeability for CO2 of 6205 barrer and a CO2/N2 and CO2/CH4 selectivity of 62.5 and 56.1, respectively, far surpassing the 2008 Robeson upper bound and exceeding most of the reported advanced membranes. As a divertive of PIPs, this work opens a window for designing and fabricating promising MMMs for task-specific membrane separations.